backfiring '70 1500

Hey guys,

I have 1970 1500 Beetle. It has been off the road for a couple of months. I went to start it up this afternoon as I will be moving it soon. It started ok, but did not sound very healthy. A lot of backfiring, loss of power and just general roughness.

It had been serviced and was running really well just before going off the road. Any suggestions for possible cause of problem?

Thanks for any suggestions.

Has the engine stayed nice and dry all that time, and not parked outside getting rained on etc ???

No water/moisture inside the dizzy cap ??? Or cracks in the cap for that matter ???

Most hassles with cars are electrical after all...

Assuming it really was running OK before it sat still, after above my next thought would be stale fuel. If the fuel you use has any ethanol component in it (eg E10), well after a couple of months there's likely to be a fair bit of water in it too (the ethanol can cause it to absorb moisture out of the air).

Plus potentially other gunk from things that aren't 100% compatible with ethanol... possibly fouling up jets in the carb. Maybe a flush of the fuel system in order...

If it's not a fuel that includes ethanol, well still possibly gunk/crap in the fuel system, but I'd really be thinking electrical.

Volksy's are normally pretty hardy beasts... I've started engines that have sat for years, stale fuel and all and they've run like a clock within just a few minutes.

Thanks for the quick reply.

Have given it another 15-20 min run. Definitely less backfiring (still only with a push of the accelerator), but still has black smoke from the exhaust, and when in gear, complete loss of power. Seems to be happy idling though.

I assure you it was running fine before I parked it. Checked the distributor cap for cracks or moisture to no avail.

I had been using premium fuel (vortex) before parking it. I would say it has sat no longer than 3 months. Would this fuel go stale so quickly.

Again, appreciate the quick reply, and any other suggestions would be fantastic.

gong_beetle wrote:Hey guys,

I have 1970 1500 Beetle. It has been off the road for a couple of months. I went to start it up this afternoon as I will be moving it soon. It started ok, but did not sound very healthy. A lot of backfiring, loss of power and just general roughness.

It had been serviced and was running really well just before going off the road. Any suggestions for possible cause of problem?

Thanks for any suggestions.

Hi
My thoughts..
sounds like its out of tune...??
are the points nice & clean and gapped properly?
run a points file thru them about 10 times to clean them..
or... Your inlet manifold heater has rusted thru...
But black smoke usually means the fuel is too rich a mixture..
FLOODING of the carby...??

no easy fix I'm afraid.... more of a Find it then fix it...

LEE

Lee,

Thanks for your suggestions. Checked the points. Points gapped properly, not spotless, but certainly didn't need to much cleaning. Carb is fine too.

Think it might be time to see if a tune-up helps. Again, the only hesitation is that it was running so well before being parked.

Thanks again.

Rob

when i got my bus going after sitting for years ,it would idle fine but not drive well,it turned out to be a blockage in the fuel supply(rusty tank) ,it would let enough through to idle but not enough to keep running at higher revs